There exist today many styles of input devices for performing operations in a computer system. The operations generally correspond to moving a cursor and making selections on a display screen. The operations can also include paging, scrolling, panning, zooming, etc. By way of example, the input devices can include buttons, switches, keyboards, mice, trackballs, touch pads, joy sticks, touch screens and the like. Each of these devices has advantages and disadvantages that can be taken into account when designing a computer system.
With touch pad instruments such as touch pads on a personal laptop computer, the movement of the input pointer on a display generally corresponds to the relative movements of the user's finger (or stylus) as the finger is moved along a surface of the touch pad. Touch screens, on the other hand, are a type of display screen that can include a touch-sensitive transparent panel (or “skin”) that can overlay the display screen. When using a touch screen, a user typically makes a selection on the display screen by pointing directly to objects (such as graphical user interface (GUI) objects) displayed on the screen (usually with a stylus or finger).
To provide additional functionality, finger and hand gestures have been implemented with some of these input devices. By way of example, in touch pads, selections can be made when one or more taps are detected on the surface of the touch pad. In some cases, any portion of the touch pad can be tapped, and in other cases a dedicated portion of the touch pad can be tapped. In addition to selections, scrolling can be initiated by using finger motion at the edge of the touch pad.
U.S. Pat. Nos. 5,612,719 and 5,590,219, assigned to Apple Computer, Inc. (which has since changed its name to Apple Inc.) describe some other uses of gesturing. U.S. Pat. No. 5,612,719 discloses an onscreen button that is responsive to at least two different button gestures made on the screen on or near the button. U.S. Pat. No. 5,590,219 discloses a method for recognizing an ellipse-type gesture input on a display screen of a computer system.
In recent times, more advanced gestures have been implemented. For example, scrolling can be initiated by placing four fingers on the touch pad so that the scrolling gesture is recognized, and thereafter moving these fingers on the touch pad to perform scrolling events. These advanced gestures, however, can be in many instances counterintuitive.